OBD2a or 2b?

[jeffsciv23]

i got an ECU for my car and i don't know what year it came from. it's a P2P for a 96-99 ex, how do i tell if it's OBD2a or OBD2b?

 

[posol]

well, you can't.

96-98 is obd2a, 99 is 2b

you can tell by looking at the pinouts-

http://www.hondata.com/techecuid.html

 

[jeffsciv23]

thanks, but my auto ecu uses all of the plugs and the manual one doesn't use the second one. would it be safe to asume that the manual one is OBD2a and not b?